Different origins of the ferromagnetic order in (Ga,Mn)As and (Ga,Mn)<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi mathvariant="normal">N</mml:mi></mml:math>

Wierzbowska, Małgorzata; Sánchez‐Portal, Daniel; Sanvito, Stefano

doi:10.1103/physrevb.70.235209

Cited by 132 publications

(135 citation statements)

References 58 publications

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“…These results are consistent with the previous pSIC 20 and SIC 21 and the LDA+U [17][18][19] calculations. The e gshell in spin up (↑) is fully occupied, and the t 2g (↑) states are almost completely filled, with Löwdin's occupation analysis 38 giving range of values 2.74-2.85.…”

Section: Resultssupporting

confidence: 83%

Hole -character and delocalization in (Ga,Mn)As revised with pSIC and MLWF approaches – Newly found spin-unpolarized gap states of s-type below 1 of Mn

Milowska

Wierzbowska

2014

Chemical Physics

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Hole sp 3 -character and delocalization in (Ga,Mn) The dilute magnetic semiconductor (Ga,Mn)As is ferromagnetic in accordance with the p-d Zener model. Hole density function (HDF) localization has been previously studied by means of the density functional theory (DFT) and non-standard DFT methods; however not for dopings near 1%. We have revised (Ga,Mn)As using the DFT with the pseudopotential self-interaction correction (pSIC) and maximally-localized Wannier functions (MLWFs), which show the sp 3 character of a HDF. Nature of HDF is extended -for low dopings and the pSIC, 70% of the HDF is located within the inter-impurities region, and contribution of the 3d-Mn states is 3-5% for 1-3% of Mn with the pSIC, and 11% with the DFT. We found that for dopings below 1%, the spin-unpolarized s-type impurity states segregate from the conduction band to the energy gap -in contrast to earlier publications. This implies that donor co-doped dilute samples would be both insulating and nonmagnetic.

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Section: Resultssupporting

confidence: 83%

Hole -character and delocalization in (Ga,Mn)As revised with pSIC and MLWF approaches – Newly found spin-unpolarized gap states of s-type below 1 of Mn

Milowska

Wierzbowska

2014

Chemical Physics

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“…Details and a test of this implementation are given in Ref. [16]. Our definition of the local occupations n σ m also differs from the Mulliken occupations n σ,Mulliken m (Ref.…”

Section: Methodsmentioning

confidence: 99%

“…On the other hand, when the LDA+U method is applied to systems which are in effect not strongly correlated, for example TiO, it fails, at least when a self-consistently calculated U is used in the calculation. 13 In the present implementation of the LDA+SIC scheme 19 , we adopted a modified pseudo-SIC approach closely akin but not identical to that in Ref. [14].…”

Section: Methodsmentioning

confidence: 99%

Effect of electron correlations in Pd, Ni, and Co monowires

Wierzbowska

Delin²,

Tosatti

2005

Phys. Rev. B

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We investigated the effect of mean-field electron correlations on the band electronic structure of Co, Ni, and Pd ultra-thin monatomic nanowires, at the breaking point, by means of densityfunctional calculations in the self-interaction corrected LDA approach (LDA+SIC) and alternatively by the LDA+U scheme. We find that adding static electron correlations increases the magnetic moment in Pd monowires, but has negligible effect on the magnetic moment in Co and Ni. Furthermore, the number of d-dominated conductance channels decreases somewhat compared to the LDA value, but the number of s-dominated channels is unaffected, and remains equal to one per spin.

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“…The relatively large effective exchange parameter for [V(Bz)] ∞ and [Mn(Bz)] ∞ is due to the DE mechanism, which usually lead to FM with a relatively high Curie temperature, e.g. the relative high Curie temperature (about 228-370 K) [29] for Mn doped GaN is due to the DE mechanism [23,30].…”

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confidence: 99%

One-Dimensional Transition Metal−Benzene Sandwich Polymers: Possible Ideal Conductors for Spin Transport

et al. 2006

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We investigate the electronic and magnetic properties of the proposed one-dimensional transition metal (TM=Sc, Ti, V, Cr, and Mn) -benzene (Bz) sandwich polymers by means of density functional calculations. [V(Bz)]∞ is found to be a quasi-half-metallic ferromagnet and half-metallic ferromagnetism is predicted for [Mn(Bz)]∞. Moreover, we show that stretching the [TM(Bz)]∞ polymers could have dramatic effects on their electronic and magnetic properties. The elongated [V(Bz)]∞ displays half-metallic behavior, and [Mn(Bz)]∞ stretched to a certain degree becomes an antiferromagnetic insulator. The possibilities to stabilize the ferromagnetic order in [V(Bz)]∞ and [Mn(Bz)]∞ polymers at finite temperature are discussed. We suggest that the hexagonal bundles composed by these polymers might display intrachain ferromagnetic order at finite temperature by introducing interchain exchange coupling.PACS numbers: 71.20.Rv, 75.75.+a, 82.35.Lr It is expected that the new generation of devices will exploit spin dependent effects, what has been called spintronics [1,2]. A challenge now facing spintronics is transmitting spin signals over long enough distances to allow for spin manipulation. An ideal device for spin-polarized transport should have several key ingredients. First, it should work well at room temperature and should offer as high a magnetoresistance (MR) ratio as possible. In this sense, a half-metallic (HM) ferromagnet with the Curie temperature higher than room temperature is highly desirable since there would be only one electronic spin channel at the Fermi energy [3]. Second, the size or diameter of the materials should be uniform for large scale applications. Carbon nanotubes (CNTs) were considered as promising one-dimensional (1D) spin mediators because of their ballistic nature of conduction and relatively long spin scattering length (at least 130 nm) [4,5]. Coherent spin transport has been observed in multiwalled CNT systems with Co electrodes. The maximum MR ratio of 9% was observed in multiwalled CNTs at 4.2 K. However, as the temperature increases to 20 K, the MR ratio goes to zero, preventing any room temperature applications [4]. A theoretical work suggested that the ferromagnetic (FM) transition-metal (TM) /CNT hybrid structures may be used as devices for spin-polarized transport to further increase the MR ratio [6]. Unfortunately, although large spin polarization is found in these systems, there is no HM behavior. Another difficulty with CNT is that the devices are unlikely to be very reproducible due to the wide assortment of tube size and helicity that is produced during synthesis. Wide variation in device behavior was reported in the CNT experiment [4].Recently, an experimental study suggested that the unpaired electrons on the metal atoms couple ferromagnetically in the multidecker organometallic sandwich Vbenzene (Bz) complexes, i.e., V n (Bz) n+1 clusters [7]. The FM sandwich clusters are supposed to serve as nanomagnetic building blocks in applications such as recording media or spintronic de...

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Different origins of the ferromagnetic order in (Ga,Mn)As and (Ga,Mn)N

Cited by 132 publications

References 58 publications

Hole -character and delocalization in (Ga,Mn)As revised with pSIC and MLWF approaches – Newly found spin-unpolarized gap states of s-type below 1 of Mn

Hole -character and delocalization in (Ga,Mn)As revised with pSIC and MLWF approaches – Newly found spin-unpolarized gap states of s-type below 1 of Mn

Effect of electron correlations in Pd, Ni, and Co monowires

One-Dimensional Transition Metal−Benzene Sandwich Polymers: Possible Ideal Conductors for Spin Transport

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